The Field of the Invention
The present invention relates to novel cementitious materials and their methods of manufacture, and more particularly, cementitious containers that are lightweight, inexpensive, waterproof, sometimes insulative, and environmentally neutral. Both disposable and reusable cementitious containers are disclosed.
The Relevant Technology
Advanced packaging techniques allow for all types of products to travel safely for long distances from their point of origin, even with lengthy and time-consuming distribution systems. Packaging containers protect their contents from environmental influences and distribution damage. They also provide a medium for the dissemination of information to the consumer; for example, product specification, ingredients, product weight, advertising, brand identification, and pricing.
Specifically, packaging containers protect items from two major destructive influences: chemical and physical. Chemical destruction relates no compositional changes resulting from a product's exposure to moisture, light, microorganisms, or gases. Although not strictly a chemical problem, packaging also provides a barrier against vermin, including rodents and insects. On the other hand, protecting against physical destruction includes restricting the physical contents of the goods, cushioning against shock and vibration encountered during distribution, and preventing the items from leaking or being crushed.
Paper manufacturing companies are spending millions of dollars to find the "perfect" package. Recently, Georgia-Pacific Corporation opened a new package technology and development center where boxes .are designed on computer screens which are connected to large cutting tables that automatically shape and perforate the cardboard for testing under many different simulated actual and artificial conditions. Businesses are demanding packaging strong enough to protect their products, light enough to make shipping cheaper, and made of recyclable materials. The amount of time spent in research and development to meet these needs is indeed staggering.
Since nearly every product must be packaged for shipping and sale, the anticipated use of packaging containers is certainly on the increase. For example, the Congressional Office of Technology Assessment predicted in 1989 that the amount of corrugated boxes manufactured annually will increase by more than ten percent through 2000. This same report states that even the amount of packaging materials used in importing goods amounts to about 2.5 million tons per year.
The standard box or carton used in shipping is made of cardboard or a similar paper product. When insulation is required, styrofoam is typically preferred because of insulation capabilities, cost, and stability. Protective packing material is typically made from paper or plastic, e.g., styrofoam or other polystyrene-type materials. Every year, 5.6 billion tons of plastic packaging are produced.
Recently, with the public's attention being focused on environmental issues, certain containment products have come under heavy scrutiny, especially disposable packing materials and boxes. Most notably subject to criticism have been styrofoam products, which typically require the use of chlorofluoro-carbons (or "CFC's") in their manufacture, as well as use of vast amounts of the ever shrinking petroleum reserves.
Unfortunately, CFC's have been linked to the destruction of the ozone layer, because they release chlorine products into the stratosphere. It is mainly because of their stability that they do not soon degrade after being first emitted. This allows them to migrate upward through the atmosphere until they reach the ozone layer in the stratosphere. Upon disintegration, it is thought that CFC's release chlorine, which is readily converted to chlorine monoxide.
The second North American National Ozone Expedition (NOZE II) and the international Airborne Antarctic Ozone Experiment, which sent planes into the ozone hole in October 1987, found strong correlations between levels of chlorine monoxide and ozone depletion. In March 1988, the Ozone Trends Panel released an analysis showing that ozone loss has been considerably greater than computer models had predicted. The panel concluded that from 1969 to 1986, ozone levels had dropped 1.7 to 3% in the latitude band 30.degree. to 64.degree. N., which covers most of the United States, Europe, the Soviet Union, and China. Wintertime depletion in the northern portion of this region was even more severe, being 5 to 6%.
Because the ozone layer acts as a filter that removes the most harmful ultraviolet ("UV") wavelengths emitted by the sun, it is believed that significant thinning may, in the future, cause widespread damage to living organisms through excessive exposure to harmful UV light.
In particular, excessive exposure to UV radiation causes sunburning of the skin of humans and animals, in addition to the burning of the retina. One of the most recent "ozone holes" was reported over the southern tip of South America and over parts of North America. There have been reports of animals in Tierra del Fuego, the southernmost region of Chile and Argentina, having developed blindness and cataracts far in excess compared to times past. There have been numerous studies and reports that have concluded that further breakdown of the ozone layer will lead to sharp increases in skin cancer and cataracts in humans.
In the manufacture of foams, including styrofoam (or blown polystyrene), CFC's (which are highly volatile liquids) are used to "puff" or "blow" the polystyrene which is then molded into the foam cups and other food containers or packing materials. In particular, CFC-12 has been the agent of choice, but was among the CFC's slated to be phased out of use.
In the interim, polystyrene manufacturers in the U.S. have been turning to HCFC-22 as a replacement for CFC-12. While less ozone-depleting than CFC-12, HCFC-22 is still implicated nevertheless. As a result, in the early 1990's, some companies have started to use pentane in the foaming process of plastics. Nevertheless, pentane is also very hazardous to the environment; further, recent studies have suggested that pentane is more easily transferred from the plastic to the product when used in a container.
As a result, there has been widespread clamor for companies to return to using more environmentally safe and low cost containers. Some environmentalists have even favored a return to more extensive use of paper products instead of polystyrene, if only because it is thought by some that paper represents the lesser of two evils. Nevertheless, although paper produces have not been linked to the destruction of the ozone layer and are biodegradable, recent studies have shown that paper more strongly impacts the environment than does styrofoam in other respects. In fact, the wood pulp and paper industry is one of the top five polluters in the United States.
In response to intense pressure by environmentalists to find a substitute for polystyrene "peanuts," which have been the packing material of choice by many in the shipping industry, Quill (the largest office supply mail-order company in the United States) tested alternatives such as paper and real popcorn. It concluded that polystyrene peanuts were superior to either of these two alternatives.
Quill's research determined that, compared to plastic, paper filler (1) takes up more space in landfills, (2) deteriorates after several recyclings, (3) is heavier, (4) taxes resources such as trees and water, and (5) releases contaminants as it degrades. As for popcorn, Quill determined that it (1) crumbles, (2) leaves a residue, (3) attracts pests, and (4) diverts farmland from food production.
Other studies have shown that where polystyrene and paper are compared head-to-head in similar products, paper is far more damaging to the environment. Although it should be noted that different studies have produced differing statistics, one study showed that products made from paper require 10 times as much steam, 14 to 20 times as much electricity, and twice as much cooling water, compared to an equivalent polystyrene product. The same study showed that the effluent from paper-making contains 10 to 40 times the amount of contaminants produced in the manufacture of polystyrene foam. Other studies have put the figure at 10 to 100.
In addition, although most containment products made from paper contain mostly unbleached paper, to the extent bleached paper is used for such purposes, the environment is impacted by a dangerous toxin produced as a by-product of paper bleaching: dioxin. Dioxin, or more accurately, 2,3,7,8-tetrachlorodibenzo[b,e][1,4]dioxin, is a highly toxic, teragenic contaminant, and is extremely dangerous even in very low quantities.
Toxic effects of dioxin in animals include anorexia, severe weight loss, hepatotoxicity, hematoporphyria, vascular lesions, chloracne, gastric ulcers, teratogenicity, and premature death. Industrial workers exposed to dioxin have frequently developed chloracne, porphyrinuria, and porphyria cutanea tarda. Most experts in the field believe that dioxin is a carcinogen.
The highest levels of dioxin found in discharge waters from paper mills are about 0.5 part per trillion. However, fish found downstream from paper pulp mills can contain nearly 200 parts per trillion of dioxin, with levels of 50 parts per trillion being not uncommon. Typical concentrations of dioxin in bleached paper products range from undetectable amounts up to about 10 parts per trillion.
Further, it is forgotten that it is often necessary to coat many paper containers with a wax or plastic material in order to give it waterproofing properties. Moreover, if insulative properties are necessary, even more drastic modifications to the paper material in the container are necessary.
As mentioned above, many types of plastic containers, as well as the coatings utilized with paper containers, are derived from fossil fuels, mainly petroleum, and share many of the environmental concerns of petroleum refinement and the petrochemical industry, which need not be repeated here.
In addition to the obvious chemical hazards of paper, plastic, and polystyrene production, an additional problem is the impact of these containers on municipal waste disposal systems throughout the country. Both polystyrene and plastics used in food containers are very slow to degrade. This is especially true when buried deep inside of landfills, and away from the corrosive effects of light, air, and water.
Similarly, although paper is touted as biodegradable, it has been known to last a remarkably long time buried deep in a municipal dump; there are reports of telephone books being lifted from garbage that had been buried for decades. This longevity of paper is further complicated since it is common to treat, coat, or impregnate the paper with various organic materials.
The Congressional Office of Technology Assessment estimated that as of October 1989 approximately 55% by volume (and almost one-half by weight) of the materials in landfills are paper and paper products, and this percentage is steadily growing. Even after recycling, paper and paperboard products comprise the largest category of materials in municipal waste facilities. Other studies show that plastic accounts for up to 20% of the waste in landfills by volume, and that figure may nearly double to 40% by the year 2000. These figures clearly indicate the impact of current packing materials on waste management. Incineration could reduce these amounts, but incineration is often the source of significant airborne pollution, especially when plastics and polystyrene products are incinerated. Even paper, which burns relatively cleanly, emits CO.sub.2 (which has been implicated as a greenhouse gas) as well as dioxin.
About the only effective way to reduce the shear volume of traditional container and packing wastes is through recycling. However, recycling is not without its contribution of large amounts of pollution into the environment in the form of fuel spent in transporting recyclables to recycling centers, as well as fuels and chemicals used in the recycling process itself.
In short, what are needed are containers used in packaging, storing, and shipping which do not require the wholesale cutting of trees in order to supply the necessary raw materials. In addition, it would be a significant advancement in the art to provide packaging containers which are more environmentally neutral, which do not require the use ozone-depleting chemicals, which do not contain hazardous chemicals like dioxin, or which do not create unsightly garbage that does not or is very slow to degrade. Moreover, it would be an even greater improvement over the prior art if such containers did not result in the contamination of the packaged goods by any of the other toxic chemical which are often put into paper.
It would be a significant advancement to provide containers which have the cushioning and insulative properties of styrofoam, but which do not contribute to the depletion of the ozone layer. Further, it would be significant that such containers and packing materials be lightweight and yet give sufficient structural support for containing, partitioning, or cushioning products therein.
From a practical point of view, such containers must necessarily be produced inexpensively at costs comparable to existing products. From a manufacturing perspective, it would be a significant advancement in the art to provide containers which can be rapidly formed while maintaining their shape outside of a mold or other external support so that they can be handled quickly after formation.
Finally, it would be a completely novel and important advancement if such containers had a chemical composition compatible with the earth into which they eventually might be disposed.
Such packaging containers are disclosed and claimed herein.